Hy Gatis,
the blinking after 2 hours driving-time is normal. I think that this is a feature to remind you making breaks on longer trips. My Board ist showing the same.
The blue cable must be unplugged, / not plugged in. If its plugged wrong, it´s causing a shortcut and the speed-signal doesn´t work anymore. Could be the problem of your gear-box.
Btw: the board doesn´t show your speed in digits. It oly uses this information to calculate ....
